Sliver feeding devices, which conduct a sliver stored in a spinning can to an open-end spinning machine, and in particular guide the sliver into a nip between a sliver draw-in cylinder and a connected feed trough, are known in various embodiments.
Customarily such sliver feeding devices have a sliver condenser with a sliver guide chute which is designed such that the sliver is securely guided over the entire area of the condenser and is gathered prior to entering the nip between the feed trough and the sliver draw-in cylinder such that all fibers always move underneath the nip and can be combed out by the opening roller.
An inlet condenser is described in German Patent Publication DE 35 01 842 A1, wherein the condenser body and the feeding trough constitute one component. This component is displaceably mounted on an eccentrically seated guide element arranged parallel with the axis of rotation of the draw-in roller. Thus, for threading the sliver, the condenser body can be moved together with the feeding trough out of the area of the draw-in roller, and after threading can be moved back into work position again. In the work position the component is arrested in a position in which the spring-biased feeding trough and the draw-in roller constitute a nip area for the sliver, with the outlet opening of the condenser body located in the immediate vicinity of the nip area. The inlet location of the sliver feeding device, i.e. the place where the sliver is threaded into the condenser, is embodied as an eyelet and has deflection edges for opening loops which may possibly form in the sliver.
Another inlet condenser is known from German Patent Publication DE 40 22 963 A1, and has a sliver guide conduit with a funnel-like condensing section and an inlet section, which laterally terminates in the condensing section and extends slanted. A diagonally arranged run-up incline forming an edge-like obstacle is provided in the transition area between the inlet section and the funnel-like condensing section. It is intended by means of the run-up incline to prevent folding of the flattened web-like sliver when entering the condensing section. With this sliver feeding device, an eyelet-like handle is also provided at the entry location for the sliver into the inlet condenser and extends around the sliver on all sides to open loops therein.
A sliver condenser is also known from the later published German Patent Publication DE 195 39 629.4, which has a sliver guide conduit with an inlet section and a funnel-like condensing section. The condensing section is oriented with its center longitudinal axis extending orthogonally with the sliver draw-in roller and has a sliver guide surface which makes a transition into the sliver guide surface of the inlet section without a change in the direction of the curvature. Furthermore, the inlet section of the sliver guide conduit is inclined at an angle in respect to a housing wall of the opening roller housing. With this sliver feeding device, the entry location at which the sliver enters the inlet condenser, is embodied as a closed inlet eye.
The above described sliver feeding devices have proven satisfactory in connection with open-end spinning machines in which both the seating of the rotor in the rotor housing and mounting of the sliver opening device within the associated sliver feeding device are fixed in a spinning box frame fastened to the machine frame. However, the known sliver feeding devices are disadvantageous if used in open-end spinning machines in which the sliver opening devices and therefore also the sliver feeding devices are integrated into or otherwise installed on pivotably seated cover elements, as described in German Patent Publication DE 43 23 213 A1.
With spinning units of such design, the sliver opening device together with the associated sliver feeding device is pivoted away to a front side when the spinning machine is opened, and in the process the sliver being delivered from the spinning can positioned underneath the spinning station into the inlet condenser is greatly stressed by buckling at the entry location into the condenser. This heavy mechanical stress of the sensitive sliver leads to fiber displacement inside the sliver, which subsequently can have a negative effect on the spinning result or can lead to an immediate sliver break.